Fix AccessibleAttached property documentation

Task-number: QTBUG-37908
Change-Id: Ib8cfa284c2be522628359f7585b0a96addfd5ed4
Reviewed-by: Jerome Pasion <jerome.pasion@digia.com>
Fix copy and paste error

Fix first error "Null pointer dereferencing" identified by static analysis from
http://www.viva64.com/en/b/0251/

Change-Id: I984d6ac2c22fddfe5ccb507f5d95d3329bed0563
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>
Reviewed-by: Lars Knoll <lars.knoll@digia.com>
Fix potential null pointer dereferencing

These were found by
http://www.viva64.com/en/b/025
most issues are rather cosmetic.

Change-Id: I7cc12610aae6a43d26bedb9b480863c0695ddfa3
Reviewed-by: Simon Hausmann <simon.hausmann@digia.com>